The person had been interviewed by police over the last couple of days.

Also, police tell WZZM that Jessica's parents have submitted DNA samples to police so investigators have her DNA on hand if needed.

Police said at a morning news conference that they are also checking the vendors who regularly visit the gas station making deliveries. They are checking some spots of spilled fluid in the parking lot of the gas station to see if that can lead to any clues.

We have crews in Norton Shores and Muskegon County today, following the investigation that began last Friday night after Jessica Heeringa disappeared from her job at the Exxon Mobile station on Sternberg Road at about 11:15pm.